Pierre Chatelain

Contact Email : Pierre.Chatelain@irisa.fr Address : Irisa / Inria Rennes Campus de Beaulieu 35042 Rennes cedex - France Tel : +33 2 99 84 74 49 Fax : +33 2 99 84 71 71 Assistant : +33 2 99 84 22 52 (Hélène de La Ruée)

Background and Position

I graduated with a Master's degree in Mathematics from the Ecole Normale Supérieure de Cachan in 2012. During the academic year 2012-2013, I worked as a research assistant within the Chair for Computer Aided Medical Procedures (CAMP) at the Technical University Munich, and the Medical Robotics Research Group at the German Aerospace Center (DLR). I am now enrolled in a joint PhD program (cotutelle) between the Lagadic team at IRISA / Inria Rennes and CAMP, under the supervision of Alexandre Krupa and Nassir Navab. My research interests include medical robotics, biomedical image analysis, computer vision and machine learning, with a specific focus on ultrasound-based visual servoing.

Research Projects

Quality-driven ultrasound-based visual servoing

This project aims at optimizing the quality of robotic ultrasound acquisitions. We use ultrasound confidence maps to estimate the quality of the ultrasound signal within the images. Using this information, we control an ultrasound probe mounted on a robotic arm in order to continuously optimize the placement of the probe. Two different approaches are considered:

• A global confidence control: the image quality is optimized globally, without caring about the image contents. This approach is intended to be used in a teleoperation scenario, where the control is shared between the automatic controller and a human operator. In this situation, the human operator steers the probe towards the desired location, and the orientation of the probe is adapted automatically in order to optimize the image quality.
• A target-specific confidence control: an anatomic target (or region of interest) is tracked in the ultrasound stream, and the aim is to find the optimal acoustic window for this specific target.

Related publications

1. P. Chatelain, A. Krupa, N. Navab. Optimization of ultrasound image quality via visual servoing. In IEEE Int. Conf. on Robotics and Automation, ICRA'15, Pages 5997-6002, Seattle, WA, May 2015.
2. P. Chatelain, A. Krupa, N. Navab. Confidence-driven control of an ultrasound probe: target-specific acoustic window optimization. In IEEE Int. Conf. on Robotics and Automation, ICRA'16, Stockholm, Sweden, May 2016.

Visual servoing for ultrasound-guided needle insertion

This project deals with control strategies to assist the insertion of a biospy needle under ultrasound guidance. One of the challenges of ultrasound-guided needle insertion is the localization of the needle. We have developed tracking algorithms to detect the full needle shape in 3D ultrasound volumes without requiring any external tracker. Using the result of this real-time tracking, we have designed two different control frameworks which show how ultrasound-based visual servoing can be used to assist the insertion of a biopsy needle:

• For probe control: the needle is inserted manually, and the ultrasound probe, mounted on a robotic arm, is controlled in order to follow the needle during the insertion. In addition, the orientation of the probe is adapted so that the needle is aligned with the central ultrasound plane, where the resolution is the highest.
• For needle steering: the needle is inserted automatically by a robotic arm. Using the current 3D shape of the probe, we perform a closed-loop duty cycling control of the needle to steer it to a predefined target.

Related publications

1. P. Chatelain, A. Krupa, M. Marchal. Real-time needle detection and tracking using a visually servoed 3D ultrasound probe. In IEEE Int. Conf. on Robotics and Automation, ICRA'13, Pages 1668-1673, Karlsruhe, Germany, May 2013.
2. P. Chatelain, A. Krupa, N. Navab. 3D ultrasound-guided robotic steering of a flexible needle via visual servoing. In IEEE Int. Conf. on Robotics and Automation, ICRA'15, Seattle, WA, May 2015.

Publications

Complete list (with postscript or pdf files if available)

Teaching

2014-2015

• Algorithmics and functional programming, ISTIC, Rennes
• Office applications, ISTIC, Rennes

2013-2014

• Data analysis, ISTIC, Rennes
• Application programming, ISTIC, Rennes
• Advanced algorithms, ENS Rennes
• C++, ENS Rennes
• Machine Learning in Medical Imaging, TUM, Munich

Student supervision

• Sarthak Pati, Master's thesis 2014. Now software developer at the University of Pennsylviania.